Overo and verdex pro COMs will boot directly from a properly prepared microSD card. This section will outline how to partition and format a bootable microSD card.

To create a bootable microSD, compatible with the·OMAP3 boot ROM, set a special geometry using the·fdisk "Expert mode". These steps also work for verdex pro COMs.
Important Notes:

- When creating a bootable microSD card for an·Overo COM,·you MUST use expert mode. This sets the correct cylinders, heads and sectors for the microSD card before you partition it.
- Gumstix recommends using a microSDHC card for Overo COMs. Only use microSD cards for verdex pro COMs.

The example below shows the steps required to set up a new microSD card of any size. The numbers shown are given for a particular 2GB microSD card. You will be directed to make a simple calculation to determine the correct values for your microSD card.
First, insert your card into the development machine's flash card slot. You may need to use a microSD to SD card adaptor to fit your slot. example the device name will be /dev/sde. Please substitute the proper device name for your machine. You can use 'mount' or 'df' to see where the card mounts on your machine. Let's unmount the device's existing file system before we get started with fdisk:

$ sudo umount /dev/sde1

Partitioning the Card
Now, launch fdisk and create an empty partition table. Note that the argument for fdisk is the entire device (/dev/sde) not just a single partition (i.e. /dev/sde1):

# sudo fdisk /dev/sde

Command (m for help): oBuilding a new DOS disklabel. Changes will remain in memory only,until you decide to write them. After that, of course, the previouscontent won't be recoverable.Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

Next, set the geometry to 255 heads, 63 sectors and a calculated value for the number of cylinders required for the particular microSD card. To calculate the number of cylinders, take the 2032664576 bytes reported above by fdisk, divide by 255 heads, 63 sectors and 512 bytes per sector: 2032664576 / 255 / 63 / 512 = 247.12 which we round·down to 247 cylinders.

Finally, write the new partition table to the card and then exit:Command (m for help): wThe partition table has been altered!Calling ioctl() to re-read partition table.WARNING: If you have created or modified any DOS 6.xpartitions, please see the fdisk manual page for additionalinformation.Syncing disks

Formatting the New Partitions
Format the first partition as an FAT file system (the -n parameter gives it a label of FAT). You can change or omit this if you like.$ sudo mkfs.vfat -F 32 /dev/sde1 -n FATmkfs.vfat 2.11 (12 Mar 2005)

Installing the Boot Files
There are three files required on the first (FAT) partition to boot your Overo.
1) MLO: the boot-loader loader - this small program is loaded into the OMAP3 processor's static RAM. It does some minimal configuration of system memory and I/O pins and then loads the second file.
2) u-boot.bin: the boot loader
3) uImage: the Linux kernel

Note: For verdex pro, MLO is not required.
You can build these yourself or download pre-built images. but these three files must be named as stated above.

After building or downloading these files, mount the FAT partition of your microSD card. The following example assumes you mount it at /media/card.$ sudo mount /dev/sde1 /media/card

Due to constraints of the mask boot ROM in the OMAP processor, MLO MUST be written first.$ sudo cp MLO-overo /media/card/MLO

At this point you have a bootable FAT partition. Lastly, untar your desired root filesystem on the ext3 partition that you created above. Do not untar your COM rootfs onto your development machine! This example assumes that you have mounted it at /media/card:$ sudo mount /dev/sde2 /media/card

U-boot Environment Refresh
U-boot comes with a default set of environment variables that can change as new versions are released. If you are updating u-boot, clear your current set of u-boot environment variables the first time you boot with the new version. Do this by breaking into u-boot and typing the following commands. (Overo ONLY).$ nand erase 240000 20000$ reset
To make additional changes to the environment, break into u-boot again, make the changes and type 'saveenv' to save. This also eliminates the "*** Warning - bad CRC or NAND, using default environment".

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PS! The order you copy MLO, u-boot and uImage to microSD FAT partition is very important. Otherwise, you may not boot from microSD card successfully.

great, loaded. right, i need to add eth0 module while the overo booting.

$ cd /etc
$ cat modules
### This file is automatically generated by update-modules"
#
# Please do not edit this file directly. If you want to change or add
# anything please take a look at the files in /etc/modutils and read
# the manpage for update-modules.
#
### update-modules: start processing /etc/modutils/ipv6
ipv6

copy my own build overo image to microSD card, boot gumstix, the eth0 still not work!!
the reason is that the latest version of bb recipes includes the smsc911x in kernal, not a module. take a look in:
$ cd /etc/network
$ cat interfaces
#auto eth0
#iface eth0 inet dhcp
#iface eth1 inet dhcp
(eth0 has been disabled)

Note: sometimes, the eth0 will down after I stopped program. To enable the eth0 manually, try:

$ ifconfig eth0 up

$ ifconfig eth0 10.0.0.xxx netmask 255.255.255.0

or

$ udhcpc

sometimes "udhcpc" does not work.
I am using

$ifdown eth0

$ifup eth0

to enable the Ethernet.

take a look if the kernel has "rsync", because i need use it to copy Qt arm-lib files from my build machine.
try if you can install "rsync" with opkg command, which is similar to yum or apt-get
$ opkg install rsync
can't install rsync
try
$ opkg update
$ opkg install rsync
still can't install.